This invention relates generally to electron tubes and particularly to a pin sensing and straightening device for television picture tubes.
Electron tubes have various electrodes to which operating voltages are applied. The operating voltages are applied to the electrodes by connector pins which pass through the envelope of the tube. Television picture tubes (kinescopes) are funnel shaped, and have a neck extending from the narrow portion of the funnel. The neck contains an electron gun which provides the electron beams to form the picture on the screen of the tube. The operating voltages necessary to provide the electron beams are applied to the electrodes of the gun by connector pins which pass through the end of the neck.
After a kinescope is completely manufactured an insulative base is applied to the neck in engagement with the connector pins. The base is configured so that a socket, which is included in the television receiver, mates with the base such that the base and socket mate in only one orientation. The socket contains contacts which engage the connector pins whereby the proper operating voltages are applied to all the connector pins of the tube. Typically, all the operating voltages are different and therefore the connector pins are electrically isolated by the base. With a kinescope, one of the electrodes receives a much higher voltage than the other electrodes of the gun. For this reason, it is essential that the pin receiving the higher voltage be electrically isolated from the other pins by a higher measure of insulation. Typically, this is accomplished by forming a silo portion in the base so that the high voltage pin is completely surrounded by an insulative material.
The manufacture of a kinescope is a complex operation and therefore the tubes go through substantial manufaturing steps after the electron guns and connector pins are sealed into the necks of the tubes. For this reason, there is risk of one or more of the electron pins being bent or otherwise damaged. When the tube base is applied to the neck, the bases typically are configured so that most of the pins are visible whereby the presence of the pins, or whether or not the pins are bent, can be determined by visual inspection. However, the high voltage pin typically is hidden in the silo and therefore visually determining whether or not the high voltage pin is bent, or present in the silo is extremely difficult. For this reason, there is a need for a device for sensing the high voltage pin contained within the silo and also for a device which will straighten bent pins. The invention fulfills these needs.